1. Field of the Invention
The present invention generally relates to interworking between networks and, more particularly, to the utilization of an InterWorking Function (IWF) as a logical Serving General Packet Radio Service (GPRS) Support Node (SGSN) for implementing a hybrid coupling arrangement between a Wireless Local Area Network (WLAN) and a mobile communications network.
2. Background of the Invention
A number of different architectures may be employed in an interworking between a Wireless Local Area Network (WLAN) coverage area and other mobile communications technologies such as Universal Mobile Telecommunications System (UMTS). As is known, WLANs offer much higher access data rates than cellular mobile networks such as UMTS, but provide very limited coverage (typically up to 100 meters from the radio transmitter), while UMTS offers widespread coverage (ranging several hundred kilometers). Interworking may be provided between a WLAN hotspot and a mobile communications network, such as UMTS, to allow a user to utilize either the WLAN or the mobile communications network, or both, depending on the location of the user. The interworking between the WLAN and the mobile communications network may provide the user with roaming capability as the user moves between, and through, the coverage areas of the WLAN and the mobile communications network in order to efficiently use the capabilities of the access networks. However, it is typically the case that the user and control planes are not separate in such an interworking and, thus, the Quality of Service (QOS) negotiations, mobility, Authentication Authorization and Accounting (MA) procedures of the UMTS are not re-used, resulting in expensive UMTS radio resources being tied up implementing these functions.
Accordingly, it would be desirable and highly advantageous to have an interworking arrangement between a WLAN and a mobile communications network (e.g., UMTS) that aids in separating the user and control planes such that the signaling still goes through the mobile communications network but the data goes through the WLAN radio resources. Such an interworking would provide the advantage that the QOS negotiations, mobility, AAA procedures of the other mobile communications network are re-used while freeing up expensive radio resources of the mobile communications network and utilizing the high data throughput of a WLAN.